Which of the following actions would constitute a failure to maintain control of a vehicle?

Swerving unexpectedly into another lane represents a failure to maintain control of a vehicle because it indicates that the driver is not able to keep the vehicle safely in their intended lane. Maintaining control involves being able to steer and maneuver the vehicle in response to road conditions, other vehicles, and traffic signals. When a driver swerves unexpectedly, it suggests a loss of situational awareness or a failure to anticipate the vehicle's behavior, potentially endangering themselves and others on the road.

In contrast, driving with a broken headlight does not necessarily reflect the driver's ability to control the vehicle, although it is unsafe and could be illegal based on vehicle equipment laws. Driving within the speed limit indicates that the driver is adhering to traffic regulations, and stopping at a red light shows compliance with traffic signals. Both of these actions demonstrate responsible driving behavior, contributing to overall control of the vehicle.